Animal and human models of impaired adipose tissue glucose utilization and insulin sensitivity will be studied. These include cultured rat adipose tissue, rats on high fat diets, glucocorticoid-treated adipose tissue, normal humans and humans with obesity, diabetes mellitus and or hypertriglyceridemia. Adipose tissue glucose utilization will be studied using many techniques designed to isolate points of defects. These include overall 14C-glucose utilization, 14C-2-deoxyglucose transport, hexokinase isoenzymes (bound and free), intracellular and extracellular fatty acids and multiple intracellular glucose metabolites. Using these measurements we will try to determine the specific steps which are impaired. Where possible the glucose utilization will be altered and changes in the responsible steps will be noted and correlated with these alterations.